A technique related to the fuel tank described above is disclosed in JP-A-2008-168766.
As illustrated in FIG. 9, the fuel tank is constituted by a fuel tank body 100, a fuel supply device 120 installed in the fuel tank body 100, and a fuel vapor treating device (illustration is omitted). The fuel tank body 100 is configured by joining an upper shell 101 and a lower shell 102 at the positions of flange portions 103 and 104 thereof.
In the left end portion of the upper portion of the upper shell 101, an inlet portion 101e to which an inlet pipe (illustration is omitted) for guiding fuel to the fuel tank body 100 from a fueling port is connected is provided to penetrate through the wall surface. In addition, in the upper surface of the upper shell 101, a vapor port 105p that communicates with a space in the fuel tank body 100 via a cut-off valve 105 is provided, and a vapor pipe of the fuel vapor treating device (illustration is omitted) is connected to the vapor port 105p. 
Moreover, in the side surface of the lower shell 102, a pipe joint 123 to which a fuel press-feeding pipe 122 of the fuel supply device 120 is connected, and a connector 127 to which a power cable 124 of a motor of the fuel supply device 120 and a signal cable 125 of a liquid level sensor are connected are provided to penetrate through the wall portion.
In the fuel tank described above, the inlet portion 101e, the vapor port 105p, the pipe joint 123, and the connector 127 are provided at different positions, and thus through-holes (illustration is omitted) need to be formed at the corresponding positions in the wall portion of the fuel tank body 100. Therefore, sealing needs to be performed at the corresponding positions of the inlet portion 101e, the vapor port 105p, the pipe joint 123, the connector 127, and the like.
As such, since the sealing points are distributed, reliability of the fuel tank against fuel leakage is reduced, and cost is increased due to the need for sealing at a plurality of points.
There has been a need for improved fuel tank to enhance reliability of a fuel tank and achieve reduction in cost by integrating sealing points of a fuel tank body into a single point.